Cooling system for rotary machines



Dec. 28,1937. T. wfNlcHoLs 2,103,632-

I v COOLING SYSTEM FOR ROTARY MACHINES Filed Jan. 31, 1936 2 Sheets-Sheet l v x I c M nsw 70,4 4114444 Dec. 28, 1937.

T. W. NICHOLS COOLING SYSTEM FOR ROTARY MACHINES Fild Jan. 51, 1956 ,2 Sheets-Sheet 2 //v l/ENTOR M 1 m. W

ATTORNEXS Patented Dec'. 28, 1937 PATENT cr nes I 7 2,103,632 COOLING SYSTEM FOR ROTARY MACHINE Thomas Wintersignor of one-half Blast (iompany,

' Manchester, England Application Nichols, London, England, as-

to Tilghmans Patent Sand Limited, Broadheath, near January 31, 1936, Serial No. 61,651

In Great Britain February 6, 1935 7 Claims.

This invention relates to the cooling of rotary compressors, exhausters and pumps and has for its object to increase the efficiency of machines of this type by the removal of more of the heat generated due to the compression of the air or gas by the machine, than when only the casing and covers are cooled.

Rotary machines of the type comprising a rotor mounted on a shaft or shafts and arranged parallel but eccentrictothe bore of the casing or statoraleaving a crescent shaped space between the rotor and the bore of the casing, the rotor having thejvanes 'or blades radially slidable in slots, havein known machines only been cooled on the outside of the casing and covers by either air or water circulated around the machine.

In machines of this type it is known that when they are used as air or gas compressors the heat of compression causes the rotor to'become very hot. The air or gas enters the suction inlet at a temperature approximating to the temperature of the atmosphere and passing into the machine meets the hot rotor from which it rapidly absorbs heat causing the air or gas to expand, so that the machine is charged with air or gas of less density than the surrounding atmosphere thereby reducing the efliciency of the machine.

It is known that water or air or both have been applied for the cooling of rotary internal combustion engines; the present application relates only to' rotary compressors, exhausters and pumps.

According to the present invention besides cooling-the outside of the casing and covers of the machine -I also oool the inside of the rotor, by circulating the cooling medium through it by meansof a fan orimpeller, or pump.

If air is used as the cooling medium, the cooling air is circulated through the rotor by means of a suitable fan, or should-the outside of the stator or casing be also cooled by air a suitable double or compound fan may be arranged on the shaft of the rotor to circulate the cooling airthrough the rotor and also circulate the cooling air over the outside of thecasing,

If water is used as the cooling medium, the cooling water may be led to the inlet end of the rotor from any suitable supply source or may be forced through'the rotor by means of a rotary water pumpp At the outlet end of the rotor a suitable impeller may be attached to the end of the shaft or coupling, the impeller being surrounded or enclosed ina suitable casing whose outlet may be connected by piping to a cooling receiver or tank. I

With the above objects inview my invention consists'in improvements in the cooling and con struction of machines of the type referred to as will be hereinafter described and claimed. The annexed drawings illustrate examples of cooling and construction of improvements comprising'the invention.- I

Fig. 1. shows a transverse vertical section of a rotary compressor on the line A-A of Fig. 2, the compressor being provided with a double or compound fan for drawing cooling air through the rotor and overthe outside of the casing of the machines.

Fig. 2 is an end view of cover removed. 7 4 Fig. 3 is a vertical section of the dual fan on the line 13-13 of Fig. 1. e r

Fig. 4 illustrates a vertical section of the outlet end of the shaft of a compressor adapted to carry animpeller enclosed in a suitable casing when water is used as the cooling medium.

Referring to Figs. 1 and 2, a, indicates the inlet to the compressor, b theoutletfrom the compressor, 0 the casing and d the rotor.

r The casing c is surrounded with anouter covering e which maybe cast with the casing attached to the casing-in any suitable manner. Ribs 7 may be provided on the casing to attach the cleading to, and also act as guides for the cooling air passing over the casing. Fins g may also be arranged between the ribs 1 to increase the cooling surface.

The rotor d may be made in any suitable manner, as for instance, it may be made solid with its shaft or shafts, butthe illustration shows a rotor which may be made from, a casting having the passages through it cored out, the rotor being secured to a shaft or shafts h as preferred. The shaft his bored and machined from its outer end to form the inlet passage It into the rotor for the cooling air. The other end of the shaft h is boredin a similar manner to form the outlet passage 1 from the rotor, a part ofthe material 7' of the shaft being left to form a separating partition between the suction inlet is and the outlet passage l. Suitable passages or ports 0, p, and 1' are arranged in the rotor d between each pair'of adjacent blades or vanes. The casing or stator c is closed at each end by suitable covers adapted to house bearings, ball and/or roller bearings being preferred to carry the shaft h. A coupling s may be secured to the outlet end of the shaft h adapted to be bolted to the coupling 15 secured to the shaft of the power unit. Between the couplingss and t and arranged to be the machine with a I V I V .25, or stator c or may be made of cleading and be securely held by the coupling bolts is arranged a double purpose or dual fan u made by the junction of the two fans w, and m, which may be separated by a partition u. The fan wdraws cooling air through the rotor d by way of the inlet port It, ports 0, p, and r situated between each pair of adjacent vanes, and port I to the inlet of the fan w arranged between the couplings s and t, and may deliver through the oleading e to the atmosphere. The fan :0 draws cooling air through the passages formed by the outside of the casing c, the cleading e and the ribs f and may deliver through the cleading e to the atmosphere. The cleading e may be perforated around its circumference with suitable holes or slots the full width of the combined fan 1) to permit the cooling air to pass to the surrounding atmosphere.

If it be preferred that the outside of the casing be cooled by water in the known manner by means of a water jacket and water circulator system, and the rotor be cooled by air, a single fan only, as for instance w, may be used for the air.

Fig. 4 illustrates a convenient outlet from the rotor when water is used as the cooling medium. The cooling water is led to the inlet end of the rotor shaft h from any suitable supply source, an elevated tank or receiver may be preferred. An impeller 11, as used in centrifugal pumps, is securely held between the couplings s and t by the coupling bolts. Surrounding the impeller :11 is a suitable casing 2 to collect the cooling water that has passed through the rotor d. The outlet 2 of the casing a may be connected by suitable piping to the elevated tank or receiver if preferred, in which case, the impeller y would be of suitable diameter to create the pressure necessary to return the cooling water to the tank.

The fan or fans 2; or the impeller 3 may be attached to the end of the rotor shaft h in any preferred manner.

The desired method of air cooling by means of a fan or fans may be adapted to any type of rotary air compressor, exhauster or pump if a passage through the rotor for the cooling air can be obtained.

I claim:--

1. A rotary pump or compressor of the eccentric type, including a stator, a housing surrounding said stator and defining a cooling chamber around said stator, a hollow shaft, a hollow rotor carried by said shaft and rotatable in said stator, inlet and outlet passages for providing communication between the interior of said shaft and said rotor whereby a cooling passage is provided through said shaft and rotor, and rotatable means carried on said shaft outside said stator and inside said housing, said means including a dual fan having sets of blades coaxial with said shaft and cooperating respectively with said cooling chamber and the interior of said shaft for urging parallel currents of cooling fluid respectively through said cooling chamber and through said passage in said shaft and rotor.

2. A rotary pump or compressor of the eccentric type including a. stator having a shaft rotatably mounted therein, a rotor mounted on said shaft for rotation in said stator, a passage for a cooling fluid through said rotor, a casing surrounding said stator and providing a passage for a cooling fluid past said stator, a fan carried coaxially by said shaft outside said stator and inside said casing for forcing a current of cooling fluid through said rotor, a second fan carried coaxially by said shaft outside said stator and inside said casing for forcing a current of cooling fluid past said stator in parallel with said first current, an opening adjacent one end of said casing for admitting a cooling fluid to said second passage and an opening adjacent the other end of said casing and communicating with both of said passages for permitting egress of cooling fluid therefrom adjacent said fans.

3. A rotary machine comprising a stator, a hollow rotor, a shaft eccentrically mounting said rotor for rotation within said stator, said shaft being substantially tubular to define a passage extending axially therethrough, a partition in said axial passage, passages providing communication between the interior of said rotor and the portions of said axial passage on each side of said partition, a. casing at least partially surrounding said stator and adapted to provide a cooling chamber around said stator, and means for establishing operatively parallel currents of a fluid cooling medium, one current passing through said cooling chamber and the other current passing through said axial passage and the interior of said rotor, said means including a plurality of centrifugal devices mounted on said shaft and constituting a unitary structure, one of said devices being positioned to urge said first current through said cooling chamber, and the other of said devices being positioned to urge said'second current through said axial passage. I

4. A rotary machine comprising a stator, a hollow rotor, a shaft eccentrically mounting said rotor for rotation within said stator, said shaft having a passage extending therethrdugh, passages providing communication between the interior of said rotor and the portions of said axial passage on each side of said rotor, a casing at least partially surrounding said stator and adapted to provide a cooling chamber around said stator, means for establishing operatively parallel currents of a fluid cooling medium, one current passing through said cooling chamber and the other current passing through said axial passage and the interior of said rotor, said means including a plurality of centrifugal devices mounted on said shaft in proximity and constituting a unitary structure, one of which devices is positioned to urge said first current through said chamber, and the other of said devices being positioned to urge said second current through said shaft, and an opening in a wall of said casing disposed in juxtaposition with both of said centrifugal devices to permit passage of both of said currents through the wall of said casing.

5. A rotary machine comprising a stator, a hollow rotor, a shaft eccentrically mounting said rotor for rotation within said stator, said shaft having a passage therein, passages providing communication between the interior of said rotor and the portions of said axial passage on each side of said rotor, a casing at least partially surrounding said stator and adapted to provide a cooling chamber around said stator, means for establishing operatively parallel currents of a fluid cooling medium, one current passing through said cooling chamber and the other current passing through the passage in said shaft and the interior of said rotor, said means including a plurality of centrifugal devices concentrically mounted on said shaft and constitut ing a unitary structure, one of which devices is positioned to urge said first current through said cooling chamber, and the other of said devices being positioned to urge said second current through the passage in said shaft, and means to permit passage of said currents through said casing.

6. A rotary machine comprising a stator, a

hollow rotor, a shaft eccentrically mounting said rotor for rotation within said stator, said shaft having a passage extending axially therethrough, passages providing communication between the interior of said rotor and the portions of said -axial passage on each side of said rotor, a casing at least partially surrounding said stator and adapted to provide a cooling chamber around said stator, means for establishing operatively parallel currents of a fluid cooling medium, one current passing through said cooling chamber and the other current passing through said axial passage and the interior of said rotor, said means including a plurality of centrifugal devices mounted on said shaft and constituting a unitary structure, one of said devices being positioned within said casing and immediately adjacent and in alignment with one end of said axial passage to urge said second current therethrough, and an opening in a'wall of said casing disposed to permit passage of said currents through the wall of said casing. I

'7. A rotary machine comprising a stator, a

hollow rotor, a shaft eccentrically mounting said rotor for rotation within said stator, said shaft being tubular to provide a passage extending axially therethrough, a partition in said axial passage, passages providing communication between. the interior of said rotor and the portions of said axial passage on each side of said partition, a casing at least partially surrounding said stator and adapted to provide a cooling chamber around said stator, means for establishing operatively parallel currents of a fluid cooling medium. one current passing through said cooling chamher and the other current passing through said axial passage and the interior of said rotor, said means including a plurality of centrifugal fans concentrically mounted on said shaft and constituting a unitary structure, one of said fans being positioned in said cooling chamber to urge said first current therethrough, and the other of i said fans being positioned immediately adjacent an end of said axial passage to urge said second current therethrough, and an opening in a wall of said casing disposed in juxtaposition with both of said fans to permit passage of said currents through the wall of said casing.

, THOMAS WINTER. NICHOLS. 

